Abstract More than 6.5 million people have heart failure (HF) in the United States and 960,000 new cases are reported annually. HF is associated with high mortality and hospitalization rates, high costs, and poor health-related quality of life (HRQL). Despite major improvements in outcomes with medical and surgical therapy, admission rates following a HF-related hospitalization remain high with 25% of patients readmitted to the hospital within 30-days and up to 50% readmitted within 6 months. Previous research shows that adherence to routine HF self-care behaviors reduces the risk of all-cause mortality and hospitalization, and improves HRQL. However, self-care has generally been found to be poor among HF patients, particularly minority populations. Nonadherence to HF symptom monitoring and medication use is remarkably high even among recently discharged patients hospitalized for an HF exacerbation. Recent advances in consumer-based mobile health (mHealth) technologies, such as smartphones, mobile health apps, wearable sensors, and other connected health devices, offer scalable and affordable solutions for promoting better HF self-care and expanding delivery of care services to communities that are difficult to reach. Leveraging our team's interdisciplinary expertise in this emerging area, we developed an innovative, patient-centered intervention (iCardia4HF) that promotes adherence to HF self-care through the use of commercial mHealth tools. iCardia4HF consists of: (1) a patient-centered mHealth app (developed in partnership with the Heart Failure Society of America) that interfaces with multiple connected health devices and comprises a number of self- monitoring, patient education, and adherence reminder tools for improving self-care; and (2) individually tailored text-messages (TMs) targeting health beliefs, self-care efficacy, and HF-knowledge. We propose a pilot randomized controlled trial (RCT) with 92 HF patients randomized 1:1 to iCardia4HF or an attention control group receiving the same connected health devices as the intervention group for 12 weeks, but without the mobile app and TMs. Specific aims are to: 1) assess the feasibility and acceptance of iCardia4HF; 2) examine the preliminary efficacy of iCardia4HF on objectively assessed measures of HF self-care using real- time data from the connected health devices and app, as well as self-reported Self-Care and HRQL; track the number of hospitalizations and emergency room (ER) visits over 12 weeks; and 3) examine the mediating effect of intervention target variables (health beliefs, self-care efficacy, and HF-knowledge) and impact of independent patient factors on HF self-care. This study represents an important step in identifying an affordable and scalable mHealth intervention that has the potential to bring about a new paradigm in self-care management of HF. Data collected from this study will help us further refine the intervention, and provide the scientific basis for a future R01-level RCT that will determine the efficacy of iCardia4HF as an adjunct to usual care for patients with HF.